Conventionally, a lamp for vehicles of such type is conventionally known (for example, Patent Literature 1). Hereinafter, a conventional lamp for vehicles will be described. The conventional lamp for vehicles is provided with a lens, a lens holder, a heat sink, and an LED light source. A plugging piece and an engagingly locking claw are formed at a peripheral edge of the lens; a plugging hole, an engagingly locking hole, and a positioning protrusion is formed in the lens holder; the plugging piece is plugged into the plugging hole; and the engagingly locking claw is engagingly locked to the engagingly locking hole. The lens is abutted against the positioning protrusion, and the lens is accurately positioned in a longitudinal direction with respect to the lens holder.